The present invention relates to a lactic acid-based resin composition and a molded article thereof. More specifically, it relates to a lactic acid-based resin composition that is excellent in moldability, flexibility and safety and is easily decomposed in the natural environment after use, and a molded article thereof.
In general, as resins that are excellent in flexibility, heat resistance and water resistance, such resins are exemplified, as polyethylene, polypropylene, plasticized polyvinyl chloride, polyethylene terephthalate and the like, and are used as a disposal bag, a packaging bag and the like. However, these resins increase the amount of waste upon discarding after use, and because they are substantially not decomposed under the natural environment, they semipermanently remain underground even when they are discarded underground. There also arise problems in that discarded plastics impair scenery and destroy the life environments of marine organisms.
In order to cope therewith, as a polymer having biodegradability, which is a thermoplastic resin, an aliphatic polyester derived from a polyhydroxycarboxylic acid, such as polylactic acid and the like, with an aliphatic polyhydric alcohol and an aliphatic polyhydric carboxylic acid, and the like are being developed.
These polymers are completely decomposed in the body of animals within several months to one year, or when they are placed in earth or ocean water, they begin to be decomposed within several weeks under a wet environment and disappear within about one year to several years. Furthermore, they have such characteristics that the decomposed products are lactic acid, carbon dioxide and water, which are harmless to human bodies.
In particular, polylactic acid is expected to have an expanded utility field owing to the facts that L-lactic acid as the raw material can be mass-produced at low cost by the fermentation process, and it exhibits a large decomposition rate in barnyard manure, and has excellent characteristics, such as the resistance to fungus, resistance to odorization and coloring of foods, and the like.
However, polylactic acid has high rigidity and thus cannot be said that it is a resin suitable for such purposes that require flexibility, such as a film, a packaging material and the like.
In general, it has been known as a method for softening a resin that a soft polymer is blended, but when a soft general-purpose resin, such as resins including polyethylene, polypropylene, polyvinyl chloride or the like, is mixed with polylactic acid, it is impossible to develop a lactic acid-based resin composition having biodegradability and flexibility, which is the object of the invention described later. Therefore, what can impart flexibility to polylactic acid through polymer blend is limited to soft biodegradable resins. As these resins, polybutylene succinate, polyethylene succinate, polyhydroxybutyric acid, polyhydroxyvaleric acid, polycaprolactone, a copolymer and a mixture thereof, and the like are exemplified, and they have been disclosed in Japanese Patent Laid-Open No. 245866/1996 and Japanese Patent Laid-Open No. 111107/1997.
However, these soft resins have poor compatibility with polylactic acid, and there are several problems upon practical use for producing a film, a filament and the like when it is simply melted and mixed. For example, upon molding a film and a filament, because they do not sufficiently attain uniform mixing even when they are subjected to heat melting and kneading in an extruder viscosity unevenness, unevenness in thickness of a film and unevenness in diameter of a thread occur, and furthermore, breakage of a film and breakage of a thread occur, whereby stable molding is difficult.
Moreover, even though a film or a thread can be obtained, upon subsequently subjecting orientation by stretching for increasing properties, such as heat resistance, strength and the like, it is liable to be broken upon stretching, whereby stable stretching cannot be carried out, or stretching cannot be carried out with sufficient magnification. As a result, the heat resistance and the strength cannot be sufficiently improved, and such a problem is caused in that a film and a thread that can be practically used cannot be obtained.
Japanese Patent Laid-Open No. 262474/1998 discloses an agricultural sheet formed with a mixture of (A) crystalline polylactic acid having a melting point of 150xc2x0 C. or more, (B) an aliphatic polyester having a melting point of 140xc2x0 C. or less formed with a linear diol and an aliphatic dicarboxylic acid as main components, and (C) a block copolymer of the polylactic acid (A) and the aliphatic polyester (B), and fibers. It is also disclosed that the mixture is improved in flowability and moldability in comparison to a simple mixture of the polylactic acid and the aliphatic polyester of a linear diol and an aliphatic dicarboxylic acid. However, there is no specific disclosure of examples, and in particular, it is expected from the description of other examples that the block copolymer (C) has a molecular weight of several hundreds of thousands. However, in the case where a block polymer having such a large molecular weight is used, the effects of improvement in flowability and moldability are not sufficiently exerted as is clear from the comparative examples described later.
As has been described, it is the current situation that it is substantially difficult that a molded article, such as a film, a filament and the like, imparted with flexibility is stably obtained with good productivity only by blending a soft biodegradable resin with polylactic acid, and furthermore, it is substantially impossible with the conventional techniques to improve properties, such as heat resistance, strength and the like, by orientation and crystallization by stretching.
In the invention, 1) a technique for effectively dispersing a soft biodegradable resin with polylactic acid, 2) development of a flexible lactic acid-based resin composition, and 3) a molded article, such as a film, a filament and the like, obtained from a flexible lactic acid-based resin composition, as well as 4) development of a production process of a molded article that is highly and effectively imparted with practical properties, such as strength, heat resistance, flexibility and the like, from polylactic acid are designated as objects.
In order to attain the objects, the inventors have designed and explored a compound for improving the compatibility between polylactic acid and a soft biodegradable resin, and as a result, such a compound has been found that has a sufficient compatibility effect with a small amount to satisfy the objects, whereby the invention has been completed.
That is, the invention is identified by the following items [1] to [12].
[1] A lactic acid-based resin composition comprising a mixture of a mixture (A) of polylactic acid (a1) and an aliphatic polyester (a2), and an aliphatic block co-polyester (B) having a polylactic acid segment and an aliphatic polyester segment, wherein the aliphatic block co-polyester (B) satisfies all the following conditions (1) to (3):
(1) it contains a lactic acid component in an amount of from 20 to 80 wt % in terms of monomer,
(2) it has a weight average molecular weight of 1,000 or more and less than 60,000, and
(3) it has a weight average molecular weight of the polylactic acid segment of from 500 to 55, 000 and a weight average molecular weight of the aliphatic polyester segment of from 500 to 55,000.
[2] A lactic acid-based resin composition described in item [1], wherein a compositional ratio of the mixture (A) and the aliphatic block co-polyester (B) is from 0.05 to 10 parts by weight of the aliphatic block co-polyester (B) per 100 parts by weight of the mixture (A).
[3] A lactic acid-based resin composition described in item [1] or [2], wherein the aliphatic polyester (a2) has an elastic modulus measured by the test method of JIS K6732 of 2,500 MPa or less.
[4] A lactic acid-based resin composition described in any one of items [1] to [3], wherein the mixture (A) of the polylactic acid (a1) and the aliphatic polyester (a2) has a mixing ratio of from 80 to 20 parts by weight of the aliphatic polyester (a2) per from 20 to 80 parts by weight of the polylactic acid (a 1).
[5] A lactic acid-based resin composition described in any one of items [1] to [4], wherein the aliphatic polyester (a2) is polybutylene succinate and/or polycaprolactone.
[6] A molded article comprising a lactic acid-based resin composition described in any one items [1] to [5].
[7] A molded article described in item [6], which is stretched in at least one direction by from 1.1 to 15 times.
[8] A molded article described in item [6] or [7], wherein the molded article is a film or a sheet.
[9] A molded article described in item [6] or [7], wherein the molded article is a tape yarn.
[10] A molded article described in item [6] or [7], wherein the molded article is a mono-filament or multi-filaments.
[11] A molded article described in item [6] or [7], wherein the molded article is a nonwoven fabric.
[12] A process of using an aliphatic block co-polyester (B) having a polylactic acid segment and an aliphatic polyester segment, as a compatibility agent for a mixture (A) of polylactic acid (a1) and an aliphatic polyester (a2), wherein the aliphatic block co-polyester (B) satisfies all the following conditions (1) to (3):
(1) it contains a lactic acid component in an amount of from 20 to 80 wt % in terms of monomer,
(2) it has a weight average molecular weight of 1,000 or more and less than 60,000, and
(3) it has a weight average molecular weight of the polylactic acid segment of from 500 to 55, 000 and a weight average molecular weight of the aliphatic polyester segment of from 500 to 55,000.
The invention will be described in detail below.
In the invention, the mixture (A) of (a1) polylactic acid and (a2) an aliphatic polyester contains from 20 to 80 parts by weight of the polylactic acid (a1) and from 80 to 20 parts by weight of the aliphatic polyester (a2).
Polylactic Acid (a1)
As lactic acid used as a raw material of the polylactic acid, L-lactic acid, D-lactic acid, DL-lactic acid, a mixture thereof, and lactide, which is a cyclic dimer of lactic acid, can be exemplified.
As specific examples of a production process of the polylactic acid used in the invention, for example,
1) a method using lactic acid as a raw material, which is directly subjected to dehydration polycondensation (for example, the production method shown in U.S. Pat. No. 5,310,865),
2) a ring opening polymerization method, in which a cyclic dimer of lactic acid (lactide) is subjected to melt polymerization (for example, the production method disclosed in U.S. Pat. No. 2,758,987),
3) a method, in which upon producing a polyester polymer by carrying out a dehydration polycondensation reaction of lactic acid in the presence of a catalyst, solid phase polymerization is carried out in at least part of the process,
and the like can be exemplified, but it is not particularly limited in the production process thereof. A small amount of an aliphatic polyhydric alcohol, such as trimethylolpropane, glycerin and the like, an aliphatic polybasic acid, such as butanetetracarboxylic acid and the like, and a polyhydric alcohol, such as a polysaccharide, may be copolymerized by coexisting, and the molecular weight may be increased by using a binder (a polymer chain extending agent), such as a diisocyanate compound and the like.
Aliphatic Polyester (a2)
The soft aliphatic polyester (a2) used in the invention is a polymer having biodegradability that can be produced by variously combining the aliphatic hydroxycarboxylic acid, the aliphatic dihydric alcohol and the aliphatic dibasic acid described later, and preferably has an elastic modulus measured by the test method of JIS K6732 of 2,500 MPa or less, more preferably from 1 to 1,500 MPa, further preferably from 5 to 1,000 MPa, still further preferably from 5 to 750 MPa, and most preferably from 5 to 500 MPa. When the elastic modulus is larger than 2,500 MPa, the softening effect upon mixing with the polylactic acid is small.
As a preferred soft aliphatic polyester shown in the invention, for example, polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, polyhydroxybutyric acid, polyhydroxyvaleric acid, a copolymer of xcex2-hydroxybutyric acid and xcex2-hydroxyvaleric acid, polycaprolactone and the like can be exemplified. In particular, polybutylene succinate, polybutylene succinate adipate and polycaprolactone are preferred from the standpoint of the elastic modulus and the easy availability with low cost.
The aliphatic polyester may be those having a polymer chain extended with a binder, such as a diisocyanate and the like, may be those copolymerized in the presence of a small amount of an aliphatic polyhydric alcohol, such as trimethylolpropane, glycerin and the like, an aliphatic polybasic acid, such as butanetetracarboxylic acid, or a polyhydric alcohol, such as polysaccharide, and further may be those crosslinked with an electron beam.
As a production method of the aliphatic polyester, the similar method as the production method of the polylactic acid may be used, and the method is not limited.
Aliphatic Hydroxycarboxylic Acid
As specific examples of the aliphatic hydroxycarboxylic acid used in the soft aliphatic polyester in the invention, glycolic acid, lactic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 6-hydroxycaproic acid and the like can be exemplified, and furthermore, acyclic ester of the aliphatic hydroxycarboxylic acid, such as glycolide, which is a dimer of glycolic acid, and xcex5-caprolactone, which is a cyclic ester of 6-hydroxycaproic acid, can be exemplified. These may be used solely or in combination of two or more of them.
Specific examples of the aliphatic dihydric alcohol used in the aliphatic polyester in the invention, for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neopentyl glycol, polytetramethylene glycol, 1,4-cyclohexanedimethanol and the like can be exemplified. These may be used solely or in combination of two or more of them.
Aliphatic Dibasic Acid
Specific examples of the aliphatic dibasic acid used in the soft aliphatic polyester in the invention, oxalic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecane diacid, dodecane diacid, phenylsuccinic acid and the like can be exemplified. These may be used solely or in combination of two or more of them.
Molecular Weight of Polylactic Acid (a1) and Aliphatic Polyester (a2)
The weight average molecular weights (Mw) and the molecular weight distributions of the polylactic acid (a1) and the aliphatic polyester (a2) are not particularly limited as far as molding fabrication can be substantially possible. The weight average molecular weights of the polylactic acid (a1) and the aliphatic polyester (a2) used in the invention are not particularly limited as far as they exhibit substantially sufficient mechanical properties, and in general, it is preferably, in terms of weight average molecular weight (Mw), from 60,000 to 1,000,000, more preferably from 80,000 to 500,000, and most preferably from 100,000 to 300,000. In general, when the weight average molecular weight (Mw) is less than 60,000, a molded article obtained by molding fabrication of the resin composition has insufficient mechanical properties, and when the molecular weight exceeds 1,000,000, there are some cases where the melt viscosity upon molding fabrication becomes extremely high to make handling difficult, and the production becomes uneconomical.
Aliphatic Block Co-polyester (B)
The aliphatic block co-polyester (B) used in the invention is a block copolymer formed with lactic acid with the aliphatic dibasic acid, the aliphatic dihydric alcohol and the aliphatic hydroxycarboxylic acid, and is a block copolymer containing from 20 to 80 wt % of a lactic acid component in terms of monomer.
As the production process of the aliphatic block co-polyester (B) relating to the invention, it can be produced, for example, by applying the method of directly subjecting lactic acid to dehydration polycondensation and the method of ring opening polymerization of lactide, which is a dimer of lactic acid, which appear in the examples for polylactic acid described in the foregoing, and for example,
1) a method, in which a monomer is subjected to ring opening polymerization to form a polymer, and then other monomer component is added to the polymer by ring opening polymerization, where one of the monomers is lactide, and
2) a method, in which a polylactic acid component directly obtained by dehydration polycondensation or ring opening polymerization and an aliphatic polyester component obtained by the similar method are mixed and subjected to dehydration polycondensation addition in the presence or absence of a catalyst and/or an organic solvent can be exemplified.
More specifically,
1) a method as shown in Production Example 51, in which caprolactone is first subjected to ring opening polymerization in the presence of a catalyst and an aliphatic alcohol to obtain the polymer, and then polymerization is carried out with lactide charged (two-step ring opening polymerization), and
2) a method as shown in Production Example 510, in which polylactic acid, which is first directly obtained by dehydration polycondensation, and the other aliphatic polyester are mixed and subjected to dehydration polycondensation in the presence of a catalyst and an organic solvent (two-step dehydration polycondensation) can be exemplified.
In the invention, it is necessary that the molecular weight and the molecular weights of the respective block units of the aliphatic block co-polyester (B) are controlled to the particular ranges. As a method therefor, a method, in which the reaction conditions, such as the reaction temperature, the time and the like upon polymerization, are appropriately changed to follow up progress of the polymerization degree, and a method of adding an end termination agent can be exemplified, and particularly, in the case of the ring opening polymerization, the method of adding an end termination agent is particularly preferred owing to the large polymerization rate.
As the end termination agent that can be used in the invention, a compound having a hydroxyl group or a carboxyl group, for example, a compound having a monofunctional group, such as an aliphatic alcohol, an aliphatic carboxylic acid and an anhydride thereof, are preferred.
As the aliphatic alcohol, for example, a saturated or unsaturated, and linear or branched aliphatic alcohol having from 1 to 30 carbon atoms is exemplified, and methanol, ethanol, propanol, iso-propanol, butanol, iso-butanol, hexanol, octanol, lauryl alcohol, palmityl alcohol, myristyl alcohol, stearyl alcohol, oleyl alcohol and the like are exemplified.
As the aliphatic carboxylic acid and an anhydride thereof, for example, a saturated or unsaturated, and linear or branched aliphatic carboxylic acid having from 1 to 30 carbon atoms is exemplified, and acetic acid, propanoic acid, iso-propanoic acid, butanoic acid, iso-butanoic acid, tert-butanoic acid, heptanoic acid, iso-heptanoic acid, pentanoic acid, octanoic acid, lauric acid, palmitic acid, stearic acid, oleic acid, erucic acid, and behenic acid are exemplified. As the end termination agent used in the invention, ethanol, lauryl alcohol, palmityl alcohol, myrystyl alcohol, stearyl alcohol and oleyl alcohol are particularly preferably used.
The addition amount of the end termination agent is suitably from 0.05 to 5 mol % based on the total molar number of the monomer units constituting the aliphatic block co-polyester, preferably from 0.1 to 3 mol %, and more preferably from 0.2 to 2 mol %. When it is less than 0.05 mol %, the molecular weight of the aliphatic block co-polyester becomes large, and as a result, there are some cases where the compatibility effect is not exerted. On the other hand, when it is more than 5 mol %, the molecular weight of the aliphatic block co-polyester becomes small, and there are some cases where not only the compatibility effect is not exerted when formed into the composition of the invention, but also the mechanical strength is lowered.
The molecular weight of the aliphatic block co-polyester (B) is particularly important, and is 1,000 or more and less than 60,000 in terms of weight average molecular weight, preferably from 1,000 to 50,000, more preferably from 3,000 to 40,000, and further preferably from 5,000 to 30,000. When it is less than 1,000, the effect as the compatibility agent disappears. When it is larger than 60,000, on the other hand, the effect of addition is not exerted.
The repeating unit of lactic acid, which is the essential component of the block copolymer, suitably has a weight average molecular weight of from 500 to 55,000, preferably from 1,500 to 50,000, more preferably from 3,000 to 40,000, and further preferably from 5,000 to 30,000.
The other repeating unit of the aliphatic polyester suitably has a weight average molecular weight of from 500 to 55,000, preferably from 1,500 to 50,000, more preferably from 3,000 to 40,000, and further preferably from 5,000 to 30,000.
Addition Amount of Aliphatic Block Co-polyester (B)
The addition amount of the aliphatic block co-polyester (B) is from 0.05 to 10 parts by weight per 100 parts by weight of the mixture (A) of the polylactic acid (a1) and the other aliphatic polyester (a2). It is preferably from 0.1 to 7 parts by weight, more preferably from 0.2 to 5 parts by weight, and further preferably from 0.3 to 3 parts by weight.
When the addition amount of the aliphatic block co-polyester (B) is less than 0.05 part by weight, there are some cases where the compatibility effect is insufficient. When it exceeds 10 parts by weight, there are some cases where the heat resistance of the lactic acid-based resin composition is lowered, and the strength of the resulting molded article is decreased because the melting point and the molecular weight of the aliphatic block co-polyester (B) are relatively small.
The aliphatic block co-polyester (B) of the invention exhibits an excellent compatibility effect when the polylactic acid (a1) and the aliphatic polyester (a2) are mixed. For example, when pellets obtained by simply melting and kneading a mixture of polylactic acid and polybutylene succinate are melted by heat and then cooled, an exothermic peak due to crystallization of the polybutylene succinate component is observed on thermal analysis with DSC, and by adding the aliphatic block co-polyester (B) of the invention to the mixture, the exothermic peak disappears. In other words, it is considered that the addition of the aliphatic block co-polyester (B) of the invention suppresses separation and rearrangement of the polybutylene succinate component in the mixture upon melting and cooling to delay crystallization of the polybutylene succinate component, whereby the excellent compatibility effect is obtained. As a result, in a molded article formed by injection molding or the like, since the polybutylene succinate component is effectively dispersed in the mixture, the resulting molded article can exert a high elongation rate even when a relatively small amount of the aliphatic block co-polyester (B) is added. In a molded article having been stretched and oriented, such as a yarn, a filament, a nonwoven fabric and the like, concentration unevenness of the respective component and thickness unevenness in a molded article before stretching are decreased by adding the aliphatic block co-polyester (B), and thus further uniform and high stretching becomes possible to obtain a molded article having high strength.
Other Additives
In the lactic acid-based resin composition of the invention, various kinds of additives (a plasticizer, an antioxidant, an ultraviolet ray absorbent, a heat stabilizer, a flame-retardant, an internal releasing agent, an inorganic additive, an antistatic agent, a surface wettability improving agent, a combustion assistant, a pigment, a lubricant and a natural matter) and the like may be added corresponding to the objects (for example, improvement in moldability, secondary workability, degradability, tensile strength, heat resistance, storage stability, weather resistance and the like).
For example, in inflation molding and T-die extrusion molding, an inorganic additive and a lubricant (an aliphatic carboxylicamide, an aliphatic carboxylic bisamide and the like) may be added for blocking prevention and improvement of sliding property of a film and a sheet.
As the inorganic additive, silica, calcium carbonate, talc, kaolin, kaolinite, carbon, titanium oxide, zinc oxide and the like are exemplified, and in particular, silica and calcium carbonate are preferred. These may be used solely or as a mixture of two or more of them.
As the organic additive, starch and a derivative thereof, cellulose and a derivative thereof, pulp and a derivative thereof, paper and a derivative thereof, flour, bean curd refuse, palm chaff, coffee sullage, protein and the like are exemplified. These may be used solely or as a mixture of two or more of them.
Production Process of Lactic Acid-Based Resin Composition
The lactic acid-based resin composition of the invention is obtained by mixing and kneading the polylactic acid (a1) with the other aliphatic polyester (a2) and the aliphatic block co-polyester (B), as well as, depending on necessity, other additives. While the method for mixing and kneading is not particularly limited, a method, in which after uniformly mixing by using a high-speed mixer or a low-speed mixer, melt kneading is carried out with a mono-axial or multi-axial extruder having sufficient kneading performance, and a method of mixing and kneading upon melting can be employed.
In general, the shape of the lactic acid-based resin composition relating to the invention is preferably pellets, bars, powder and the like.
Molded Article and Production Process Thereof
The lactic acid-based resin composition of the invention is a preferred material that can be applied to the known molding methods, and as the resulting molded article, while not limited, for example, a film, a sheet, a mono-filament, multi-filaments, such as fibers, a nonwoven fabric and the like, an injection-molded article, a blow-molded article, a laminated article, a foamed article, a heat-molded article, such as vacuum-molded article and the like.
The lactic acid-based resin composition of the invention is good in molding property upon orientation and crystallization by stretching, and because the effect of the invention is markedly exhibited thereupon, it is preferred for the production of a film, a sheet, a tape yarn, a stretched blow-molded product, mono- and multi-filaments and a nonwoven fabric that are obtained by stretching.
As a molding method of the molded article obtained from the lactic acid-based resin composition of the invention, an injection molding method, a blow molding method (injection stretching blow, extrusion stretching blow and direct blow), a balloon method, an inflation method, a co-extrusion method, a calender method, a hot press method, a solvent casting method, a (stretching) extrusion method, an extrusion lamination method with paper or aluminum, contour extrusion molding, thermoforming such as vacuum (pressure) forming, melt spinning (a mono-filament, multi-filaments, a spun-bonding method, a melt-blown method, a fibrillated film yarn method and the like), a foaming molding method, a compression molding method and the like can be exemplified, and it can be applied to any method.
In particular, in the case of a molding method, such as extrusion molding, melt spinning and the like, containing steps of orientation and crystallization, the practical strength and the appearance, such as strength, heat resistance, impact resistance, transparency and the like, of the resulting molded article can be improved, and thus is can be more preferably used.
The molded article obtained by the lactic acid-based resin composition of the invention encompasses molded articles obtained by the known molding methods, and the shape, the size, the thickness, the design and the like thereof are not limited.
Specific Examples of Purpose
The molded article obtained by molding the lactic acid-based resin composition of the invention by using the foregoing molding methods can be preferably used as materials for wide ranges including various kinds of wrapping films for foods, electronics, medical use, pharmaceuticals, cosmetics and the like, and materials used in the fields of agriculture, civil engineering and fishery, for example, a bottle, a film or a sheet, a hollow tube, a laminated article, a vacuum (pneumatic) molded article, mono- or multi-filaments, a nonwoven fabric, a foamed article, a shopping bag, a paper bag, a shrink film, a disposal bag, a compost bag, a lunch box, a bag for prepared foods, a packaging film for foods and confections, a wrapping film for foods, a wrapping film for cosmetics and perfumes, a diaper, a sanitary napkin, a wrapping film for pharmaceuticals, a wrapping film for a surgical patch drug applied to stiff neck, sprain and the like, a film for agriculture and horticulture, a wrapping film for agricultural chemicals, a film for green houses, a bag for manure, a packaging band, a packaging film for a magnetic tape cassette, such as those for video, audio and the like, a wrapping form for floppy disks, a film for prepress, an adhesive tape, a tape, a yarn, a pot for raising of seedling, a waterproof sheet, a soil bag, a building film, a weed-control sheet, a vegetation net and the like.